Glitchy Fizz at Base Gate?

So, I recently went into a LoL game as fizz and at the beginning, I felt like trying to get out before the gate disappeared. I started with E, so I went up to the gate and used my E twice so that didnt work. After that I tried to flash out and that's where the problem is. When I used flash nothing happened then a second later Fizz just teleported back to where he stood in the trickster mode. I went and performed this many times in custom games and it happened every time.

Watch the Bug here: https://youtu.be/1SOVu0r0tZk